Infrared spectroscopy is a rapid and noninvasive analytical characte-rization technique applied in dating of wooden artefacts (heritage samples) based on the correlation between the chemical characteristics of the wood in dependence with the specific storage conditions and the dated or estimated period of time. IR spectroscopy is also used for qualitative and quantitative analyses of wood species (hard- and softwood) based on their functional groups abundance and particular structural composition (relative propor-tions of lignin and carbohydrates), as well as for evaluation of chemical changes during natural or artificial weathering, chemical and biological de-gradation processes. Thus, by this method it becomes possible to evaluate archeological wood samples properly dated or unknown, the effectiveness of applied conservation treatments and the correlation between the wood species, the history of fabrication and use, the ageing time and environmen-tal conditions. In this study, we report on the application of IR spectroscopy in anal-ysis of wood, from heritage objects whose date is known from indirect sources, and comparison with the artificial weathering samples of softwood (fir, pine, spuce) and hardwood (oak, walnut, ash, cherry, maple, linden,pear trees) species, in laboratory controlled conditions. The influence of ageing conditions: humidity, UV irradiation intensity and exposure time was correlated with the degree of aging /age of dated samples. The evolu-tion of the degradation process was followed in the same controlled ageing conditions after the application of some chemical treatments on wood sam-ples, consisting of lignin and lignin/castor and argan oils mixture, as alter-natives in the sustainable conservation of wood for art and heritage objects. *Aknowledgements: This work was supported by a grant of the Romanian Ministry of Research, Innovation and Digitalization, CNCS - UEFISCDI, project number PN-III-P4-IDPCE-2020-2000, within PNCDI III, Contract 207/2021 (2DPerMONSil).